[thirdparty/git.git] / read-cache.c

/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"

const char *sha1_file_directory = NULL;
struct cache_entry **active_cache = NULL;
unsigned int active_nr = 0, active_alloc = 0;

void usage(const char *err)
{
	fprintf(stderr, "read-tree: %s\n", err);
	exit(1);
}

static unsigned hexval(char c)
{
	if (c >= '0' && c <= '9')
		return c - '0';
	if (c >= 'a' && c <= 'f')
		return c - 'a' + 10;
	if (c >= 'A' && c <= 'F')
		return c - 'A' + 10;
	return ~0;
}

int get_sha1_hex(char *hex, unsigned char *sha1)
{
	int i;
	for (i = 0; i < 20; i++) {
		unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
		if (val & ~0xff)
			return -1;
		*sha1++ = val;
		hex += 2;
	}
	return 0;
}

char * sha1_to_hex(unsigned char *sha1)
{
	static char buffer[50];
	static const char hex[] = "0123456789abcdef";
	char *buf = buffer;
	int i;

	for (i = 0; i < 20; i++) {
		unsigned int val = *sha1++;
		*buf++ = hex[val >> 4];
		*buf++ = hex[val & 0xf];
	}
	return buffer;
}

/*
 * NOTE! This returns a statically allocated buffer, so you have to be
 * careful about using it. Do a "strdup()" if you need to save the
 * filename.
 */
char *sha1_file_name(unsigned char *sha1)
{
	int i;
	static char *name, *base;

	if (!base) {
		char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
		int len = strlen(sha1_file_directory);
		base = malloc(len + 60);
		memcpy(base, sha1_file_directory, len);
		memset(base+len, 0, 60);
		base[len] = '/';
		base[len+3] = '/';
		name = base + len + 1;
	}
	for (i = 0; i < 20; i++) {
		static char hex[] = "0123456789abcdef";
		unsigned int val = sha1[i];
		char *pos = name + i*2 + (i > 0);
		*pos++ = hex[val >> 4];
		*pos = hex[val & 0xf];
	}
	return base;
}

int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
{
	unsigned char real_sha1[20];
	SHA_CTX c;

	SHA1_Init(&c);
	SHA1_Update(&c, map, size);
	SHA1_Final(real_sha1, &c);
	return memcmp(sha1, real_sha1, 20) ? -1 : 0;
}

void *map_sha1_file(unsigned char *sha1, unsigned long *size)
{
	char *filename = sha1_file_name(sha1);
	int fd = open(filename, O_RDONLY);
	struct stat st;
	void *map;

	if (fd < 0) {
		perror(filename);
		return NULL;
	}
	if (fstat(fd, &st) < 0) {
		close(fd);  
		return NULL;
	}
	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	close(fd);
	if (-1 == (int)(long)map)
		return NULL;
	*size = st.st_size;
	return map;
}

void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
{
	int ret, bytes;
	z_stream stream;
	char buffer[8192];
	char *buf;

	/* Get the data stream */
	memset(&stream, 0, sizeof(stream));
	stream.next_in = map;
	stream.avail_in = mapsize;
	stream.next_out = buffer;
	stream.avail_out = sizeof(buffer);

	inflateInit(&stream);
	ret = inflate(&stream, 0);
	if (sscanf(buffer, "%10s %lu", type, size) != 2)
		return NULL;

	bytes = strlen(buffer) + 1;
	buf = malloc(*size);
	if (!buf)
		return NULL;

	memcpy(buf, buffer + bytes, stream.total_out - bytes);
	bytes = stream.total_out - bytes;
	if (bytes < *size && ret == Z_OK) {
		stream.next_out = buf + bytes;
		stream.avail_out = *size - bytes;
		while (inflate(&stream, Z_FINISH) == Z_OK)
			/* nothing */;
	}
	inflateEnd(&stream);
	return buf;
}

void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
{
	unsigned long mapsize;
	void *map, *buf;

	map = map_sha1_file(sha1, &mapsize);
	if (map) {
		buf = unpack_sha1_file(map, mapsize, type, size);
		munmap(map, mapsize);
		return buf;
	}
	return NULL;
}

int write_sha1_file(char *buf, unsigned len)
{
	int size;
	char *compressed;
	z_stream stream;
	unsigned char sha1[20];
	SHA_CTX c;

	/* Set it up */
	memset(&stream, 0, sizeof(stream));
	deflateInit(&stream, Z_BEST_COMPRESSION);
	size = deflateBound(&stream, len);
	compressed = malloc(size);

	/* Compress it */
	stream.next_in = buf;
	stream.avail_in = len;
	stream.next_out = compressed;
	stream.avail_out = size;
	while (deflate(&stream, Z_FINISH) == Z_OK)
		/* nothing */;
	deflateEnd(&stream);
	size = stream.total_out;

	/* Sha1.. */
	SHA1_Init(&c);
	SHA1_Update(&c, compressed, size);
	SHA1_Final(sha1, &c);

	if (write_sha1_buffer(sha1, compressed, size) < 0)
		return -1;
	printf("%s\n", sha1_to_hex(sha1));
	return 0;
}

int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
{
	char *filename = sha1_file_name(sha1);
	int fd;

	fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
	if (fd < 0)
		return (errno == EEXIST) ? 0 : -1;
	write(fd, buf, size);
	close(fd);
	return 0;
}

static int error(const char * string)
{
	fprintf(stderr, "error: %s\n", string);
	return -1;
}

static int verify_hdr(struct cache_header *hdr, unsigned long size)
{
	SHA_CTX c;
	unsigned char sha1[20];

	if (hdr->signature != CACHE_SIGNATURE)
		return error("bad signature");
	if (hdr->version != 1)
		return error("bad version");
	SHA1_Init(&c);
	SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
	SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
	SHA1_Final(sha1, &c);
	if (memcmp(sha1, hdr->sha1, 20))
		return error("bad header sha1");
	return 0;
}

int read_cache(void)
{
	int fd, i;
	struct stat st;
	unsigned long size, offset;
	void *map;
	struct cache_header *hdr;

	errno = EBUSY;
	if (active_cache)
		return error("more than one cachefile");
	errno = ENOENT;
	sha1_file_directory = getenv(DB_ENVIRONMENT);
	if (!sha1_file_directory)
		sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
	if (access(sha1_file_directory, X_OK) < 0)
		return error("no access to SHA1 file directory");
	fd = open(".dircache/index", O_RDONLY);
	if (fd < 0)
		return (errno == ENOENT) ? 0 : error("open failed");

	size = 0; // avoid gcc warning
	map = (void *)-1;
	if (!fstat(fd, &st)) {
		size = st.st_size;
		errno = EINVAL;
		if (size >= sizeof(struct cache_header))
			map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
	}
	close(fd);
	if (-1 == (int)(long)map)
		return error("mmap failed");

	hdr = map;
	if (verify_hdr(hdr, size) < 0)
		goto unmap;

	active_nr = hdr->entries;
	active_alloc = alloc_nr(active_nr);
	active_cache = calloc(active_alloc, sizeof(struct cache_entry *));

	offset = sizeof(*hdr);
	for (i = 0; i < hdr->entries; i++) {
		struct cache_entry *ce = map + offset;
		offset = offset + ce_size(ce);
		active_cache[i] = ce;
	}
	return active_nr;

unmap:
	munmap(map, size);
	errno = EINVAL;
	return error("verify header failed");
}
Commit	Line	Data
8bc9a0c7 LT	1	/*
	2	* GIT - The information manager from hell
	3	*
	4	* Copyright (C) Linus Torvalds, 2005
	5	*/
e83c5163 LT	6	#include "cache.h"
	7
	8	const char *sha1_file_directory = NULL;
	9	struct cache_entry **active_cache = NULL;
	10	unsigned int active_nr = 0, active_alloc = 0;
	11
	12	void usage(const char *err)
	13	{
	14	fprintf(stderr, "read-tree: %s\n", err);
	15	exit(1);
	16	}
	17
	18	static unsigned hexval(char c)
	19	{
	20	if (c >= '0' && c <= '9')
	21	return c - '0';
	22	if (c >= 'a' && c <= 'f')
	23	return c - 'a' + 10;
	24	if (c >= 'A' && c <= 'F')
	25	return c - 'A' + 10;
	26	return ~0;
	27	}
	28
	29	int get_sha1_hex(char hex, unsigned char sha1)
	30	{
	31	int i;
	32	for (i = 0; i < 20; i++) {
	33	unsigned int val = (hexval(hex[0]) << 4) \| hexval(hex[1]);
	34	if (val & ~0xff)
	35	return -1;
	36	*sha1++ = val;
	37	hex += 2;
	38	}
	39	return 0;
	40	}
	41
	42	char * sha1_to_hex(unsigned char *sha1)
	43	{
	44	static char buffer[50];
	45	static const char hex[] = "0123456789abcdef";
	46	char *buf = buffer;
	47	int i;
	48
	49	for (i = 0; i < 20; i++) {
	50	unsigned int val = *sha1++;
	51	*buf++ = hex[val >> 4];
	52	*buf++ = hex[val & 0xf];
	53	}
	54	return buffer;
	55	}
	56
	57	/*
	58	* NOTE! This returns a statically allocated buffer, so you have to be
	59	* careful about using it. Do a "strdup()" if you need to save the
	60	* filename.
	61	*/
	62	char sha1_file_name(unsigned char sha1)
	63	{
	64	int i;
	65	static char name, base;
	66
	67	if (!base) {
	68	char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
	69	int len = strlen(sha1_file_directory);
70	base = malloc(len + 60);
71	memcpy(base, sha1_file_directory, len);
72	memset(base+len, 0, 60);
73	base[len] = '/';
74	base[len+3] = '/';
75	name = base + len + 1;
76	}
77	for (i = 0; i < 20; i++) {
78	static char hex[] = "0123456789abcdef";
79	unsigned int val = sha1[i];
80	char pos = name + i2 + (i > 0);
81	*pos++ = hex[val >> 4];
82	*pos = hex[val & 0xf];
83	}
84	return base;
85	}
86
2ade9340 LT	87	int check_sha1_signature(unsigned char sha1, void map, unsigned long size)
	88	{
	89	unsigned char real_sha1[20];
	90	SHA_CTX c;
	91
	92	SHA1_Init(&c);
	93	SHA1_Update(&c, map, size);
	94	SHA1_Final(real_sha1, &c);
	95	return memcmp(sha1, real_sha1, 20) ? -1 : 0;
	96	}
	97
24778e33	98	void map_sha1_file(unsigned char sha1, unsigned long *size)
e83c5163	99	{
e83c5163	100	char *filename = sha1_file_name(sha1);
24778e33 LT	101	int fd = open(filename, O_RDONLY);
	102	struct stat st;
	103	void *map;
e83c5163	104
e83c5163 LT	105	if (fd < 0) {
	106	perror(filename);
	107	return NULL;
	108	}
	109	if (fstat(fd, &st) < 0) {
24778e33	110	close(fd);
e83c5163 LT	111	return NULL;
	112	}
	113	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	114	close(fd);
	115	if (-1 == (int)(long)map)
	116	return NULL;
24778e33 LT	117	*size = st.st_size;
	118	return map;
	119	}
	120
	121	void * unpack_sha1_file(void map, unsigned long mapsize, char type, unsigned long *size)
	122	{
	123	int ret, bytes;
	124	z_stream stream;
	125	char buffer[8192];
	126	char *buf;
e83c5163 LT	127
	128	/* Get the data stream */
	129	memset(&stream, 0, sizeof(stream));
	130	stream.next_in = map;
24778e33	131	stream.avail_in = mapsize;
e83c5163 LT	132	stream.next_out = buffer;
	133	stream.avail_out = sizeof(buffer);
	134
	135	inflateInit(&stream);
	136	ret = inflate(&stream, 0);
	137	if (sscanf(buffer, "%10s %lu", type, size) != 2)
	138	return NULL;
24778e33	139
e83c5163 LT	140	bytes = strlen(buffer) + 1;
	141	buf = malloc(*size);
	142	if (!buf)
	143	return NULL;
	144
	145	memcpy(buf, buffer + bytes, stream.total_out - bytes);
	146	bytes = stream.total_out - bytes;
	147	if (bytes < *size && ret == Z_OK) {
	148	stream.next_out = buf + bytes;
	149	stream.avail_out = *size - bytes;
	150	while (inflate(&stream, Z_FINISH) == Z_OK)
	151	/* nothing */;
	152	}
	153	inflateEnd(&stream);
	154	return buf;
	155	}
	156
24778e33 LT	157	void * read_sha1_file(unsigned char sha1, char type, unsigned long *size)
	158	{
	159	unsigned long mapsize;
	160	void map, buf;
	161
	162	map = map_sha1_file(sha1, &mapsize);
	163	if (map) {
	164	buf = unpack_sha1_file(map, mapsize, type, size);
	165	munmap(map, mapsize);
	166	return buf;
	167	}
	168	return NULL;
	169	}
	170
e83c5163 LT	171	int write_sha1_file(char *buf, unsigned len)
	172	{
	173	int size;
	174	char *compressed;
	175	z_stream stream;
	176	unsigned char sha1[20];
	177	SHA_CTX c;
	178
	179	/* Set it up */
	180	memset(&stream, 0, sizeof(stream));
	181	deflateInit(&stream, Z_BEST_COMPRESSION);
	182	size = deflateBound(&stream, len);
	183	compressed = malloc(size);
	184
	185	/* Compress it */
	186	stream.next_in = buf;
	187	stream.avail_in = len;
	188	stream.next_out = compressed;
	189	stream.avail_out = size;
	190	while (deflate(&stream, Z_FINISH) == Z_OK)
	191	/* nothing */;
	192	deflateEnd(&stream);
	193	size = stream.total_out;
	194
	195	/* Sha1.. */
	196	SHA1_Init(&c);
	197	SHA1_Update(&c, compressed, size);
	198	SHA1_Final(sha1, &c);
	199
	200	if (write_sha1_buffer(sha1, compressed, size) < 0)
	201	return -1;
	202	printf("%s\n", sha1_to_hex(sha1));
	203	return 0;
	204	}
	205
	206	int write_sha1_buffer(unsigned char sha1, void buf, unsigned int size)
	207	{
	208	char *filename = sha1_file_name(sha1);
19b2860c	209	int fd;
e83c5163 LT	210
	211	fd = open(filename, O_WRONLY \| O_CREAT \| O_EXCL, 0666);
	212	if (fd < 0)
	213	return (errno == EEXIST) ? 0 : -1;
	214	write(fd, buf, size);
	215	close(fd);
	216	return 0;
	217	}
	218
	219	static int error(const char * string)
	220	{
	221	fprintf(stderr, "error: %s\n", string);
	222	return -1;
	223	}
	224
	225	static int verify_hdr(struct cache_header *hdr, unsigned long size)
	226	{
	227	SHA_CTX c;
	228	unsigned char sha1[20];
	229
	230	if (hdr->signature != CACHE_SIGNATURE)
	231	return error("bad signature");
	232	if (hdr->version != 1)
	233	return error("bad version");
	234	SHA1_Init(&c);
	235	SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
	236	SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
	237	SHA1_Final(sha1, &c);
	238	if (memcmp(sha1, hdr->sha1, 20))
	239	return error("bad header sha1");
	240	return 0;
	241	}
	242
	243	int read_cache(void)
	244	{
	245	int fd, i;
	246	struct stat st;
	247	unsigned long size, offset;
	248	void *map;
	249	struct cache_header *hdr;
	250
	251	errno = EBUSY;
	252	if (active_cache)
	253	return error("more than one cachefile");
	254	errno = ENOENT;
	255	sha1_file_directory = getenv(DB_ENVIRONMENT);
	256	if (!sha1_file_directory)
	257	sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
	258	if (access(sha1_file_directory, X_OK) < 0)
	259	return error("no access to SHA1 file directory");
	260	fd = open(".dircache/index", O_RDONLY);
	261	if (fd < 0)
	262	return (errno == ENOENT) ? 0 : error("open failed");
	263
19b2860c	264	size = 0; // avoid gcc warning
e83c5163 LT	265	map = (void *)-1;
e83c5163 LT	266	if (!fstat(fd, &st)) {
e83c5163 LT	267	size = st.st_size;
e83c5163 LT	268	errno = EINVAL;
59c1e249	269	if (size >= sizeof(struct cache_header))
e83c5163 LT	270	map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
	271	}
	272	close(fd);
	273	if (-1 == (int)(long)map)
	274	return error("mmap failed");
	275
	276	hdr = map;
	277	if (verify_hdr(hdr, size) < 0)
	278	goto unmap;
	279
	280	active_nr = hdr->entries;
	281	active_alloc = alloc_nr(active_nr);
	282	active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
	283
	284	offset = sizeof(*hdr);
	285	for (i = 0; i < hdr->entries; i++) {
	286	struct cache_entry *ce = map + offset;
	287	offset = offset + ce_size(ce);
	288	active_cache[i] = ce;
	289	}
	290	return active_nr;
	291
	292	unmap:
	293	munmap(map, size);
	294	errno = EINVAL;
	295	return error("verify header failed");
	296	}
	297